Lecture 1 Flashcards
Free water clearance
low number=we are conserving water
high number=we are getting rid of water
Renal clearance
volume of plasma/min
Aortic Arterial pressure
100mmHg. Beginning of system
Venae Cavae
0mmHg. End of system
CVP value
Normal.
elevated-sick, laying down
Pulse pressure
the difference in SBP and DBP. 120-80=40 normal
Flexible arteries=low PP
Stiff arteries=high PP
Aorta
stretchy to accommodate volume. keeps load low. secondary reservoir. keeps blood flowing in between Heart beats
Large arteries
Stiffer than aorta, higher PP
Compliance
describes how stretchy.
Formula: delta v/delta p
Elastance
How rigid something is. Inverse of compliance.
High compliance=low elastane
High elastance=low compliance
Systemic arteries areβ¦.
less compliant. Thick wall
systemic veins areβ¦
more compliant. Major blood reservoir.
mPAP
16mmHg
Pressure leading into the left heart(LAP)
2mmHg
Delta P-Pulmonary
16-2
Normal PAP
25/8
Pulmonary Circulation hasβ¦
less resistance, vessel are relatively compliant
Left Atrium pressures
2-5
Left ventricle pressure
2-100
Right Atrial Pressure
0-4
Right Ventricular pressure
0-25
Arterioles
very thick wall
Veins
Thin walls, have smooth muscle, low vascular resistance
and internal pressure.
Capillaries
- have the highest cross sectional area
- donβt respond to pressors
Velocity in aorta compared to the venae cavae
lower velocity in the venae cavae
Velocity formula
V=Flow/Area
Spewed out by the capillaries.
H+, CO2, adenosine-these tell the arteriole to relax
Most important colloids in orderβ¦
Albumin, Globulins, Fibrinogen. All together add up to a pressure of 28.
Low colloid pressure
concerned that fluid will go into places that are bad
Norepinephrine
secreted by nervous system. Blood vessels have innervation. Capillaries do not.
Lymphatic system
2L/day can increase 20 fold. One way valves. Returned to the subclavian vein.
For each 13.6mm(1.36) of distance under the heartβ¦
we will see an increase of 1mmHg in BP
BP in foot..
in about 90mmHg higher
Isogravametric reference point
When standing BP at the isogravametric point is who much higher?
6mmHg. This is due to a column of fluid starting at the upper chest. Without gravity it would be 0.
Sagital Sinus Pressure
-10mmHg. No one way valves. Rigid. Jugular veins would collapse.
Blooding pooling in the lower extremities relies on..
movement through one way valves. Paralytics will cause you to lose this.
Conductance
Diameter to the 4th power
Pousilles Law
Vascular compliance
change in volume/change in pressure
Vascular distensibility
change in volume/change in pressure x original volume
Systemic veins are how many times more distensible than systemic arteries?
8x
Cerebral circulation
less porous, tighter junctions. Electrolytes and glucose will stay put.
Turbulent Flow
noisy, inefficient. Cause coagulation, scarring of blood vessel walls, weaken. Aorta-turbulent flow and wide diameter.
Laminar Flow
fastest through the middle, slower near the walls
Reynoldβs number
over 2000, will have turbulent blood flow. Formula-Re=volume x density x diameter/viscosity
Femoral Artery
Pulse pressure greatest here
What is the main controller of BP?
Baroreceptors
What type of baroreceptors are in the carotid sinus?
stretch sensors. The higher the pressure, the more they stretch and will fire more often.
Heringβs nerve
innervates the baroreceptors of the carotid sinus. Branch of CN IX
Glossopharyngeal nerve
Cranial Nerve IX. Feed into medulla(lower part of the brain stem)
NTS(Nucleus Tractus Solitarius)
important blood pressure control site in the medulla of the brain stem
Aortic baroreceptors
secondary set of baroreceptors. Work at higher pressures, 20-30mmHg. Back up system for higher blood pressures. S curve farther to the right. Send information back to the NTS through the vagus nerve(CN X)
Blood gas sensors
Take over at very low blood pressures. under 40mmHg
Carotid artery occlusion
will cause high blood pressures d/t low pressures downstream to the occlusion.
How many phases does the cardiac cycle have?
4
What is Phase 1?
- Filling.
- AV open(mitral).
- Pressure is atria is higher than ventricle(2-5mmHg).
- Starts with 50cc(ESV)
- Add 70cc, end with 120cc(EDV)
What is Phase 2?
- Isovolumetric contraction.
- All 4 valves are closed at the beginning of phase 2.
What is Phase 3?
- Ejection.
- Pressure in ventricle exceeds the pressure in the aorta.
- Aortic valve opens at the beginning of phase 3.
- Afterload
- Pressure peaks at 120mmHg
- Aortic valve closes at the end of phase 3
What is phase 4?
Isovolumetric relaxation
Preload
really low pressure(2-5)
ESV
50cc
EDV
120cc
Afterload
Pressure that is in the aorta that the heart has to push against.